Modern inventory systems, such as those in mail order warehouses, supply chain distribution centers, airport luggage systems, and custom-order manufacturing facilities, face significant challenges in responding to requests for inventory items. As inventory systems grow, the challenges of simultaneously completing a large number of packing, storing, and other inventory-related tasks increase substantially. In inventory systems tasked with responding to large numbers of diverse inventory requests, inefficient utilization of system resources, including space and equipment, can result in lower throughput. As the capabilities of inventory systems are expanded, improvements in safety can be made as well.